Abstract

It is often claimed that classical control was a product almost entirely of the wartime laboratories of the USA and, to a lesser extent, the UK. This paper demonstrates, however, that by the end of 1940 the majority of the fundamental building blocks of this body of theory were also fairly widely known in the USSR. In particular, a conference held in Moscow in late 1940, but little known outside Russia, included papers on, and discussion of: the Nyquist criterion; operator methods; transient response; the use of the operator exp(-Tp) to model a time delay of T seconds; and the | z | < 0 criterion for the stability of a sampled-data system.